In conventional pneumatic tires, a wedge is installed at the side of the bead so that the bead portion of the tire is not released from the rim when the tire is deflated or at low air pressure. As one example of prior art, U.S. Pat. No. 5,971,047 is illustrated in FIG. 1. As shown in the figure, the upper part of carcass ply 3 winds a wedge 2 and is turned up, and then spherical bead 1 is installed wound on the carcass ply. This art requires many manufacturing steps and has many problems as described below.
First, the process of installing the bead and the wedge is very complicated, and there is a possibility that the bead is released from the rim due to the movement of the spherical bead applied when the tire is deflated. Moreover, since the hardness of the wedge 2 used is low, a shore hardness of about 95 or lower, the wedge 2 can be deformed partially on the portion suppressed by the bead 1, and cannot perform the desired role.